This is a four-day trip in Karkonosze along the Czech-Polish border. Despite their English official name (Giant Mountains) the mountains are anything but giant, with the highest peak at 1603 m a.s.l. (which, by the way, is the highest peak in Czechia), but very picturesque. They do not pose any technical difficulties but you should be reasonably fit to be able to enjoy the trip as some of the planned days are quite long.
The plan is as follows:
Thu, May 18, 16.5 km, 650 m elevation gain: driving from Vienna to Harrachov (about 5-5.5 hours), leaving the cars in Harrachov and walking to the village Spindleruv Mlyn, where we will stay overnight (in four double/twin-bedded rooms).
Fri, May 19, 19.5 km, almost 1000 m elevation gain: hiking from Spindleruv Mlyn through Sniezka (that's the highest peak) to the mountain hut Odrodzenie (https://www.schroniskoodrodzenie.pl/), where we will sleep in two four-bedded rooms.
Sat, May 20, 15-17 km, depending on the route, around 400 m up and almost 1000 m down: a long hike on the plateau through Szrenica and going down to an iconic town on the Polish side, Szklarska Poręba (it should be possible to take a ski lift down to Szklarska Poręba, in case we are tired), spending the night there.
Sun, May 21: from Szklarska Poręba we will take the scenic train ride (about 45 min) back to Harrachov, from where we will drive back to Vienna.
You can see the first three days of the trip here: https://pl.mapy.cz/s/docuboboso
Costs: fuel (with four people per car this shouldn't drain our pockets too much), one Czech vignette (around €13; Mateusz and I have a yearly one, that's why only one is needed), around €115 in total for the accommodation (one place includes breakfast) plus food (2 x breakfast, 4 x lunch, 3 x dinner) which should be around €100-120 but, of course, this will largely depend on the depth of your stomach). All in all, the whole trip should not cost more than 250€ per person.